import bmesh
# ...
bm = bmesh.new()
# ...
bm.verts.new(...)

minX = min([co[0] for co in coords])
maxX = max([co[0] for co in coords])
minY = min([co[1] for co in coords])
maxY = max([co[1] for co in coords])
minZ = min([co[2] for co in coords])
maxZ = max([co[2] for co in coords])
print(minX, maxX, minY, maxY, minZ, maxZ)